744 



THE AMEBIC 



' HALT ST 



[Vol. XLVII 



Plus differences. . 

 Minus differences. 



All difference* 



Thus by combining normal and abnormal germinations 

 there is stronger evidence for an increase in mean seed 

 weight by a selective death rate than when the normal 

 germinations alone are considered. This point will be 

 taken up again. 



Just here it is necessary to point out that in this series 

 merely the capacity for germination of the seeds in sand 

 is taken into account, whereas in the former study only 

 those were considered viable which had produced fertile 

 plants. In combining normal and abnormal seedlings 

 and contrasting them with those which failed to germi- 

 nate at all, we are undoubtedly considerably overesti- 

 mating the capacity for survival in nature. 15 



